Make must_not_suspend lint see through references when drop tracking is enabled See #97333. With drop tracking enabled, sometimes values that were previously linted are now considered dropped and not linted. This change makes must_not_suspend traverse through references to still catch these values. Unfortunately, this leads to duplicate warnings in some cases (e.g. [dedup.rs](https://cs.github.com/rust-lang/rust/blob/9a74608543d499bcc7dd505e195e8bfab9447315/src/test/ui/lint/must_not_suspend/dedup.rs#L4)), so we only use the new behavior when drop tracking is enabled. cc ``@guswynn``